Isuzu Repair: 99 Isuzu Amigo, inhibitor switch, throttle positioning sensor

Question
I'm also having what I think are electrical. I haven't started by checking the battery but I will. Here are the things I'm having trouble with:  The fuel gauge shows empty and the gas light is always on.  
The Transmission shifts hard, I've had the fluid flushed and replaced, never thought about it possibly being a grounding issue.
It appears to overheat, even when you use the heat. The previous owner changed the radiator and I'm not sure its the right one.  
Any suggestions on some of the more basic, simple things to check?


Answer
Well howdy keith! Your fuel level sending unit is bad. 100% positive. look on ebay for one. they have it for 20.00 bucks. VERY EASY TO FIX. four bolts, 3 hoses and 3 wires. wala you can drop your fuel tank. Your throttle positioning sensor sounds at fault, or inhibitor switch. Does your coolent mysteriously dissappear? If so, check your coolent hoses that run underneath your manifold for any cracks. Rodeo has bad problems with these.let me know how this goes.